I would really like to try this UI, however, upon downloading, I found that I am for some reason unable to log in when attempting to use this suite.

Login error reads "Battle.net Error #107 - There was a problem logging in with this account. You may not have a World of Warcraft game attached to your account, or you may be logging into a region different from the one you created your account in."

I only get this when I'm attempting to log in with these files, and when I set back to my old setup, it works fine.

EDIT:
I fiddled around with it and found that I need to change the settings in the WTF folder.
If anyone else wants to try this and uses enUS servers, you need to do this, too:
-Go to your World of Warcraft/WTF folder
-Open Config.WTF in notepad or a similar text file editor
-Change the first two lines (should be 'locale' and 'patchlist') to...